Treatment agent for carbon fiber precursor and carbon fiber precursor

Abstract

To improve the spinning convergence of a wound carbon fiber precursor, suppress the generation of flame-retardant fluff when the carbon fiber precursor is flame-retardant treated to produce a flame-retardant fiber, and improve the strength of carbon fiber obtained from the carbon fiber precursor.SOLUTION: A treatment agent for carbon fiber precursors according to the present invention contains a silicone compound (A), and is characterized in that the silicone compound (A) contains at least one selected from a phenyl-modified silicone (A1) and an aralkyl-modified silicone (A2).SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a treatment agent for a carbon fiber precursor and a carbon fiber precursor.

Background Art

[0002] As a method for producing carbon fiber, a technique of spinning a fibrous material and then firing the material is widely used, and this fibrous material is called a carbon fiber precursor. As the carbon fiber precursor, a material in which a treatment agent for a carbon fiber precursor adheres to the surface of a fiber material such as a polymer may be used. Such a treatment agent is used for the purpose of improving the handleability of the carbon fiber precursor in various processes when producing carbon fiber.

[0003] Japanese Patent Application Laid-Open No. 2002-129481 (Patent Document 1) discloses a synthetic fiber treatment agent for carbon fiber production that contains at least a specific amino-modified polyorganosiloxane having an amino-modifying group in the side chain of the main chain and a specific polycyclic aromatic compound in a total amount of a predetermined amount or more and both in a predetermined ratio. The carbon fiber produced by applying the treatment agent described in Patent Document 1 can simultaneously and sufficiently prevent the fusion of the flame-retardant fibers in the flame-retardant process and the occurrence of thread breakage in the flame-retardant process.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] After going through processes such as spinning, stretching, drying, and applying a treatment agent continuously, carbon fiber precursors are generally wound up by a winding device such as a winder. In this continuous process, the carbon fiber precursors pass through each process while being guided by a guiding tool such as a roller. The carbon fiber precursors to which the treatment agent described in Patent Document 1 is applied had room for improvement in terms of improving the bundling property of the wound carbon fiber precursors, suppressing the generation of flame-resistant fuzz when producing flame-resistant fibers by subjecting the carbon fiber precursors to a flame-resistant treatment, and improving the strength of the carbon fibers obtained from the carbon fiber precursors.

[0006] Therefore, there is a demand for a treatment agent for carbon fiber precursors that can improve the spinning bundling property of the wound carbon fiber precursors, suppress the generation of flame-resistant fuzz when producing flame-resistant fibers by subjecting the carbon fiber precursors to a flame-resistant treatment, and improve the strength of the carbon fibers obtained from the carbon fiber precursors, as well as the realization of carbon fiber precursors to which the treatment agent is applied.

Means for Solving the Problems

[0007] The treatment agent for carbon fiber precursors according to the present invention contains a silicone compound (A) and nonionic surfactant (N) and is characterized in that the silicone compound (A) The refractive index measured with a digital refractometer at 25°C is 1.420 to 1.600 contains at least one selected from phenyl-modified silicone (A1) and The refractive index measured with a digital refractometer at 25°C is 1.420 to 1.600 aralkyl-modified silicone (A2).

[0008] The carbon fiber precursor according to the present invention is characterized in that a treatment agent for carbon fiber precursors is adhered thereto.

[0009] According to these configurations, it is possible to achieve all of improving the spinning bundling property of the wound carbon fiber precursors, suppressing the generation of flame-resistant fuzz when producing flame-resistant fibers by subjecting the carbon fiber precursors to a flame-resistant treatment, and improving the strength of the carbon fibers obtained from the carbon fiber precursors.

[0010] Hereinafter, preferred embodiments of the present invention will be described. However, the scope of the present invention is not limited by the preferred embodiment examples described below.

[0011] In one aspect, the treatment agent for carbon fiber precursors according to the present invention is such that the nonionic surfactant (N) contains a plurality of compounds (n) in which at least one selected from ethylene oxide and propylene oxide is added to alcohol, and it is preferable that the alcohols are two or more kinds having different chemical formulas.

[0012] According to this configuration, the generation of flame-resistant fluff can be more reliably suppressed.

[0013] In one aspect, the treatment agent for carbon fiber precursors according to the present invention is such that, with the total content of the silicone compound (A) and the nonionic surfactant (N) being 100 parts by mass, the content of the silicone compound (A) is 10 parts by mass or more and 90 parts by mass or less, and the content of the nonionic surfactant (N) is 10 parts by mass or more and 90 parts by mass or less.

[0014] According to this configuration, it is possible to achieve, at a high level, an improvement in the spinning convergence of the wound carbon fiber precursors, suppression of the generation of flame-resistant fluff when the carbon fiber precursors are flame-resistant treated to produce flame-resistant fibers, and an improvement in the strength of the carbon fibers obtained from the carbon fiber precursors.

[0015] In one aspect, the treatment agent for carbon fiber precursors according to the present invention preferably further contains an amino-modified silicone (A3) as the silicone compound (A).

[0016] According to this configuration, the strength of the carbon fibers is further improved.

[0017] In one aspect, the treatment agent for carbon fiber precursors according to the present invention preferably further contains a polyether-modified silicone (A4) as the silicone compound (A).

[0018] According to this configuration, the spinning convergence of the carbon fiber precursor is further improved.

[0019] The further features and advantages of the present invention will become clearer from the following description of exemplary and non-limiting embodiments.

Embodiments for Carrying Out the Invention

[0020] Embodiments of the treatment agent for carbon fiber precursor and the carbon fiber precursor according to the present invention will be described. Hereinafter, an example in which the treatment agent for carbon fiber precursor according to the present invention (hereinafter, may be simply referred to as "treatment agent") is applied to the treatment of carbon fiber precursor will be described.

[0021] 〔Configuration of Treatment Agent for Carbon Fiber Precursor〕 The treatment agent for carbon fiber precursor according to the present embodiment contains a silicone compound (A), and the silicone compound (A) contains at least one selected from a phenyl-modified silicone (A1) and an aralkyl-modified silicone (A2). Further, the treatment agent for carbon fiber precursor according to the present embodiment may further contain a nonionic surfactant (N) as necessary.

[0022] (Silicone Compound) The silicone compound (A) contains at least one selected from a phenyl-modified silicone (A1) and an aralkyl-modified silicone (A2), but may further contain an amino-modified silicone (A3) and / or a polyether-modified silicone (A4) as necessary.

[0023] The refractive index of phenyl-modified silicone (A1) and aralkyl-modified silicone (A2) The refractive index of is desirably 1.420 to 1.600. The refractive index of phenyl-modified silicone (A1) and aralkyl-modified silicone (A2) The refractive index of is correlated with its modification rate, and the higher the modification rate, the higher the refractive index tends to be. The refractive index is measured with a digital refractometer at 25°C. Also, The kinematic viscosity of phenyl-modified silicone (A1) and aralkyl-modified silicone (A2) The kinematic viscosity of is, 300mm 2 / s to 6000mm 2 / s is desirable. The kinematic viscosity is measured using a Cannon-Fenske viscometer at 25°C.

[0024] Also, the kinematic viscosity of the amino-modified silicone (A3) is preferably 90 mm 2 / s to 8000 mm 2 / s. The amino equivalent of the amino-modified silicone (A3) is preferably 1000 g / mol to 5000 g / mol.

[0025] Also, the kinematic viscosity of the polyether-modified silicone (A4) is preferably 600 mm 2 / s to 1700 mm 2 / s. The mass ratio of the silicone main chain / polyether side chain of the polyether-modified silicone (A4) is preferably 30 / 70 to 60 / 40. The molar ratio of ethylene oxide / propylene oxide of the polyether-modified silicone (A4) is preferably 50 / 50 to 20 / 80.

[0026] (Non-ionic surfactant) The non-ionic surfactant (N) can be any non-ionic surfactant commonly used in the art. The non-ionic surfactant (N) may be a single compound or a mixture of multiple compounds.

[0027] Preferably, the non-ionic surfactant (N) contains a plurality of compounds in which at least one selected from ethylene oxide and propylene oxide is added to an alcohol, and the alcohols are two or more kinds having different chemical formulas.

[0028] Examples of the above alcohols applicable to the non-ionic surfactant (N) include, but are not limited to, tristyrenated phenol, distyrenated phenol, nonylphenol, dodecanol, tetradecanol, octadecanol, nonanol, etc.

[0029] Examples of the above compounds include, for example, a compound obtained by adding 15 moles of ethylene oxide and 10 moles of propylene oxide to 1 mole of tristyrenated phenol, A compound obtained by adding 15 moles of ethylene oxide and 10 moles of propylene oxide to 1 mole of distyrenated phenol, A compound obtained by adding 10 moles of ethylene oxide to 1 mole of nonylphenol, A compound obtained by adding 5 moles of ethylene oxide to 1 mole of dodecanol, A compound obtained by adding 10 moles of ethylene oxide to 1 mole of dodecanol, A compound obtained by adding 5 moles of ethylene oxide to 1 mole of tetradecanol, A compound obtained by adding 10 moles of ethylene oxide to 1 mole of tetradecanol, A compound obtained by adding 10 moles of ethylene oxide to 1 mole of octadecanol, Examples include a compound obtained by adding 5 moles of ethylene oxide to 1 mole of nonanol, etc. Regarding the number of moles of ethylene oxide added, 5 to 15 moles are preferable, and regarding the number of moles of propylene oxide added, 5 to 15 moles are preferable.

[0030] Regarding the treatment agent according to this embodiment, with the total content of the silicone compound (A) and the nonionic surfactant (N) being 100 parts by mass, the content of the silicone compound (A) is preferably 10 parts by mass or more and 90 parts by mass or less, and the content of the nonionic surfactant (N) is preferably 10 parts by mass or more and 90 parts by mass or less.

[0031] (Other components) The treatment agent according to this embodiment may contain components other than the silicone compound (A) and the nonionic surfactant (N). Examples of such other components include, but are not limited to, preservatives, antistatic agents, antioxidants, ultraviolet absorbers, defoamers, etc.

[0032] [Method for producing treatment agent for carbon fiber precursor] The treatment agent according to this embodiment can be obtained by mixing, in addition to the silicone compound (A), a nonionic surfactant (N) as required and components optionally added by a known method.

[0033] [Carbon fiber precursor] The carbon fiber precursor according to this embodiment is in a state where the treatment agent according to this embodiment adheres to a fiber material generally used as a carbon fiber precursor. The fiber material referred to here is a fibrous material that becomes a carbon fiber through a firing process, and can be a polyacrylonitrile-based fiber, a polyamide-based fiber, a polyester-based fiber, a polyolefin-based fiber, a cellulose-based fiber, a lignin-based fiber, a phenolic resin, pitch, etc., or a combination thereof.

[0034] As a method for attaching the treatment agent to the fiber material, a method usually used in the art for attaching this type of treatment agent to the fiber material can be applied. That is, an immersion oiling method, a spray oiling method, a roller oiling method, a guide oiling method, etc. can be adopted. In addition, when applying each method, the treatment agent can be appropriately diluted with a solvent such as water.

[0035] In the carbon fiber precursor according to this embodiment, the adhesion amount of the treatment agent is not particularly limited. For example, it is preferable that 0.3 mass% or more and 3 mass% or less of the treatment agent adheres to the entire carbon fiber precursor to which the treatment agent has adhered.

[0036] [Other embodiments] The present invention can be a treatment agent for carbon fiber precursors, which contains a silicone compound (A), and the silicone compound (A) contains at least one selected from phenyl-modified silicone (A1) and aralkyl-modified silicone (A2).

[0037] In this treatment agent for carbon fiber precursors, the refractive index of the silicone compound (A) can be 1.420 to 1.600. Further, this treatment agent for carbon fiber precursors can further contain a nonionic surfactant (N). According to these configurations, the generation of flame-retardant fluff can be further suppressed.

[0038] Regarding other configurations as well, it should be understood that all the embodiments disclosed in this specification are illustrative in all respects, and the scope of the present invention is not limited thereby. A person skilled in the art will easily understand that appropriate modifications can be made without departing from the spirit of the present invention. Therefore, other embodiments modified without departing from the spirit of the present invention are naturally included in the scope of the present invention. [Examples]

[0039] Hereinafter, the present invention will be further described with reference to examples. Note that the following examples do not limit the present invention.

[0040] 〔Preparation of Treatment Agent for Carbon Fiber Precursor〕 By the following method, Examples 1 to 33, Reference Examples 1 and 2, and Comparative Examples 1 and 2 of for the carbon fiber precursor were obtained.

[0041] (1) Reagents (Silicone Compound) As the silicone compound (A), seven types of phenyl-modified silicones (A1-1) to (A1-7) and three types of aralkyl-modified silicones (A2-1) to (A2-3) having different kinematic viscosities and refractive indices were used. Each silicone compound (A) is shown in Table 1 below.

Table 1

[0042] In addition, as the amino-modified silicone (A3), the following A3-1 to A3-4 were used. A3-1: Amino-modified silicone having a kinematic viscosity of 650 mm 2 / s and an amino equivalent of 1800 g / mol A3-2: Amino-modified silicone having a kinematic viscosity of 90 mm 2 / s and an amino equivalent of 5000 g / mol A3-3: Amino-modified silicone having a kinematic viscosity of 4500 mm 2 / s and an amino equivalent of 1200 g / mol A3-4: Amino-modified silicone having a kinematic viscosity of 8000 mm 2 / s and an amino equivalent of 1000 g / mol

[0043] In addition, as the polyether-modified silicone (A4), the following A4-1 to A4-3 were used. A4-1: A polyether-modified silicone having a kinematic viscosity of 1700 mm 2 / s, silicone main chain / polyether side chain = 50 / 50 (mass ratio), ethylene oxide / propylene oxide = 50 / 50 (molar ratio) polyether-modified silicone A4-2: Kinematic viscosity at 25°C is 600 mm 2 / s, silicone main chain / polyether side chain = 30 / 70 (mass ratio), ethylene oxide / propylene oxide = 100 / 0 (molar ratio) polyether-modified silicone A4-3: Kinematic viscosity at 25°C is 1000 mm 2 / s, silicone main chain / polyether side chain = 60 / 40 (mass ratio), ethylene oxide / propylene oxide = 20 / 80 (molar ratio) polyether-modified silicone

[0044] (Non-ionic surfactant) As the non-ionic surfactant (N), N-1 to N-10 shown in Table 2 below were used.

Table 2

[0045] The non-ionic surfactants (N-1) to (N-10) contain any of the following compounds (n-1) to (n-9) in which at least one selected from ethylene oxide and propylene oxide is added to an alcohol in the ratios shown in Table 2 above. Also, as the alcohol, tristyrenated phenol, distyrenated phenol, nonylphenol, dodecanol, tetradecanol, octadecanol, or nonanol was used. Note that the non-ionic surfactants (N-1) to (N-5), (N-7), (N-8) are examples containing two types of compounds, the non-ionic surfactant (N-6) is an example containing three types of compounds, and the non-ionic surfactants (N-9) and (N-10) are examples containing one type of compound.

[0046] n-1: A compound obtained by adding 15 moles of ethylene oxide and 10 moles of propylene oxide to 1 mole of tristyrenated phenol Compound obtained by adding 15 moles of ethylene oxide and 10 moles of propylene oxide to 1 mole of distyrenated phenol n-3: Compound obtained by adding 10 moles of ethylene oxide to 1 mole of nonylphenol n-4: Compound obtained by adding 5 moles of ethylene oxide to 1 mole of dodecanol n-5: Compound obtained by adding 10 moles of ethylene oxide to 1 mole of dodecanol n-6: Compound obtained by adding 5 moles of ethylene oxide to 1 mole of tetradecanol n-7: Compound obtained by adding 10 moles of ethylene oxide to 1 mole of tetradecanol n-8: Compound obtained by adding 10 moles of ethylene oxide to 1 mole of octadecanol n-9: Compound obtained by adding 5 moles of ethylene oxide to 1 mole of nonanol

[0047] (Other components) The following were used as other components. Diluent: Ion-exchanged water

[0048] (2) Preparation of treatment agent for carbon fiber (Preparation of Example 1) 55 parts by mass of phenyl-modified silicone (A1-1) of silicone compound (A), 10 parts by mass of amino-modified silicone (A3-1), 5 parts by mass of polyether-modified silicone (A4-1), and 30 parts by mass of nonionic surfactant (N-1) were weighed and put into a beaker. After thoroughly mixing the above components, 300 parts by mass of ion-exchanged water was gradually added while stirring to prepare a treatment agent for carbon fiber precursor of Example 1.

[0049] (Other examples , Reference Example and comparative examples) The treatment agents for carbon fiber precursors of each example were prepared in the same manner as in Example 1, except that the types and parts by mass of the reagents to be mixed were changed. The preparation conditions of all examples including Example 1 are shown in Tables 3 to 5 below.

[0050] [Evaluation of Treatment Agent for Carbon Fiber Precursor] (1) Preparation of Carbon Fiber (1-1) Preparation of Fiber Material A copolymer having a limiting viscosity of 1.80, consisting of 95% by mass of acrylonitrile, 3.5% by mass of methyl acrylate, and 1.5% by mass of methacrylic acid, was dissolved in dimethylacetamide (DMAC) to prepare a spinning dope having a polymer concentration of 21.0% by mass and a viscosity of 500 poise at 60°C. The spinning dope was discharged at a draw ratio of 0.8 from a spinneret having a pore diameter (inner diameter) of 0.075 mm and 12,000 holes into a coagulation bath of a 70% by mass aqueous solution of DMAC maintained at a spinning bath temperature of 35°C. The coagulated fiber was stretched 5-fold simultaneously with desolvation in a water washing tank to prepare an acrylic fiber strand in a water-swollen state.

[0051] (1-2) Preparation of Carbon Fiber Precursor For the prepared acrylic fiber strand, a 3% ion-exchanged aqueous solution of the treatment agent for the carbon fiber precursor of each example of the examples , Reference Example,[[]] and comparative examples was oiled by the dipping method so that the adhesion amount of the treatment agent was 1% by mass (excluding the solvent). Thereafter, the acrylic fiber strand with the treatment agent adhered thereto was subjected to a drying densification treatment with a heating roller at 150°C, and further stretched 1.7 times between heating rollers at 130°C, and then wound around a bobbin to obtain a carbon fiber precursor.

[0052] (2) Evaluation of Spinning Convergence Examples , Reference Example,[[]] For the treatment agents of each example of the examples and comparative examples, the preparation of the carbon fiber precursor according to the procedure of (1) above was continuously carried out, and the convergence state when passing through the heating roller at 130°C in the drying densification step was visually observed and evaluated according to the following three criteria. A: When the fibers are converged and the width of the fiber bundle (tow width) is relatively narrow and the width of the fiber bundle is constant B: When the fibers are converged but the width of the fiber bundle is not constant

[0053] (3) Evaluation of Flame-Retardant Fuzz Examples , Reference Example,[[]] Flame-retardant fibers were created by performing a flame-retardant treatment on the carbon fiber precursors obtained using the treatment agents of each example of the examples and comparative examples. For these flame-retardant fibers, the presence or absence of fuzz generation in the roller part during conveyance was visually observed and evaluated according to the following four criteria. AA: No fuzz is visible at all (0 to 1 fuzz location in 100 m), when there are no problems in operation A: Slight fuzz is visible (2 to 3 fuzz locations in 100 m), but it is not at a level that causes problems in operation B: Some fuzz is visible (4 to 5 fuzz locations in 100 m), but it is not at a level that causes problems in operation C: A large amount of fuzz (6 or more fuzz locations in 100 m), winding around the roller also occurs, and there are problems in operation

[0054] (4) Strength Examples , Reference Example,[[]] Carbon fibers were created by performing a firing process on the carbon fiber precursors obtained using the treatment agents of each example of the examples and comparative examples. For these carbon fibers, the strength of the carbon fibers was measured according to JIS R 7606 and evaluated according to the following three criteria. A: Strength is 4.0 GPa or more and less than 4.5 GPa B: Strength is 3.5 GPa or more and less than 4.0 GPa C: Strength is less than 3.5 GPa

[0055] 〔Results〕 Examples , Reference Example,[[]] The raw material compositions and the results of each evaluation of each example of the examples and comparative examples are shown in Tables 3 to 5.

[0056] Table 3: Examples 1 to 22

Table 3

[0057] Table 4: Examples 23 to 33 and Reference Examples 1 and 2

Table 4

[0058] Table 5: Comparative Examples 1 and 2 [Table 5]

Industrial Applicability

[0059] The present invention can be used, for example, in the production of carbon fiber precursors.

Claims

1. containing a silicone compound (A), The treatment agent for a carbon fiber precursor is characterized in that the silicone compound (A) contains at least one selected from phenyl-modified silicone (A1) and aralkyl-modified silicone (A2).

2. The treatment agent for a carbon fiber precursor according to Claim 1, wherein the refractive index of the silicone compound (A) is 1.420 to 1.

600.

3. The treatment agent for a carbon fiber precursor according to Claim 1, further containing a nonionic surfactant (N).

4. The treatment agent for a carbon fiber precursor according to Claim 3, wherein the nonionic surfactant (N) contains a plurality of compounds (n) in which at least one selected from ethylene oxide and propylene oxide is added to an alcohol, and the alcohols are two or more kinds having different chemical formulas.

5. The treatment agent for a carbon fiber precursor according to Claim 3, wherein the total content of the silicone compound (A) and the nonionic surfactant (N) is 100 parts by mass, the content of the silicone compound (A) is 10 parts by mass or more and 90 parts by mass or less, and the content of the nonionic surfactant (N) is 10 parts by mass or more and 90 parts by mass or less.

6. The treatment agent for a carbon fiber precursor according to Claim 1, wherein the silicone compound (A) further contains amino-modified silicone (A3).

7. The treatment agent for a carbon fiber precursor according to Claim 1, wherein the silicone compound (A) further contains polyether-modified silicone (A4).

8. A carbon fiber precursor, characterized in that the treatment agent for a carbon fiber precursor according to any one of Claims 1 to 7 is adhered thereto.

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